The Definition of Secondary

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In football, the secondary is the name given to the group of players that make up the defensive backfield. The defensive backs that comprise the secondary play behind the linebackers, or set out near the sidelines.

Purpose

The main purpose of the secondary is to defend against pass plays. The defensive backs accomplish this by covering wide receivers in a man or zone scheme from the line of scrimmage, and trying to intercept the pass, or at least knocking it down to force an incomplete pass.

The secondary is responsible for all longer pass attempts that go past the linebackers, and it serves as the last line of defense on all other plays that developed closer to the line of scrimmage, such as running or screen plays. When such a play breaks through the defensive line and the linebackers, the secondary is all that stands between the ball-carrier and the end zone. Thus, members of the secondary need to be able to make open field tackles, in addition to having to cover pass attempts.

Formation

A traditional secondary includes two cornerbacks and two safeties. Additional specialty defensive backs, such as nicklebacks and dimebacks, can be brought into the formation in place of linemen or linebackers when there is a need to cover additional receivers.

Positions

A secondary is made up of:

Cornerback(s): Cornerbacks play to the outside of the linebackers and cover receivers. They are expected to defend pass plays and make open field tackles.

Cornerbacks are typically among the fastest players on the field as they have to keep up with the wide receivers. They also have to be able to anticipate what the quarterback may do, and execute a wide variety of coverages.

Safety: Safeties typically line up ten or fifteen yards off of the line of scrimmage; behind the linebackers and cornerbacks.

Safeties serve as the last line of defense. If a ball carrier gets past the defensive line and the linebackers, the safety is in charge of preventing a touchdown. Thus, they are expected to be reliable open-field tacklers.

There are two variations of the position: strong safety and free safety. Their duties vary based on the defensive scheme.  The strong safety typically lines up to the tight end’s side of an offensive formation, which is also known as the strong side, hence the name strong safety. Often, the strong safety’s coverage responsibility will be the tight end or a running back from out of the backfield.

Nickelback: A nickelback is a cornerback or safety who serves as the fifth defensive back in the secondary. A typical base secondary contains four defensive backs (two cornerbacks and two safeties). Adding an extra defensive back makes five total, hence the term “nickel”.

Dimeback: A dimeback is a cornerback or safety who serves as the sixth defensive back in the secondary. Dimebacks are used when a defense employs a “Dime” formation, which uses six defensive backs, rather than the traditional four. A Dime defense is used for improved pass coverage.

Example: The secondary includes the cornerbacks, safeties, and any other defensive backs used in nickel and dime formations.